A linear programming upper bound approach to the shakedown limit of thin shells subjected to variable thermal loading

Abstract

This paper describes an upper bound technique for the evaluation of the shakedown limit of thin cyclindrical shells subject to thermal loading. The method is based upon the upper bound kinematic shakedown theorem of Koiter. By suitable choice of displacement field, in a finite element form, and yield surface, the problem is reduced to a linear programming problem. A number of solutions are presented involving a tube subjected to a moving temperature front which indicates that the technique provides, in an efficient way, a complete description of the load levels at which ratchetting would occur and the corresponding modes of deformation. The technique seems therefore, to provide a useful intermediary between the use of the simple rules incorporated in design codes and full inelastic analysis.